Skull,orbit temporal bones,facial bones,paranasal sinuses,mandible and opg

SKULL, ORBIT, TEMPORAL BONE,FACIAL
BONES AND PARANASAL SINUSES,
MANDIBLE AND OPG

SKULL (22 BONES)
CRANIUM (21 BONES)
MANDIBLE
CRANIAL VAULT (NEUROCRANIUM) FACIAL SKELETON (VISCEROCRANIUM)
(8 BONES) (14 BONES INCLUDING MANDIBLE)

CRANIAL VAULT/ CALVARIA/ BRAIN BOX/NEUROCRANIUM (8 BONES)
PAIRED BONES
1. PARIETAL
2. TEMPORAL
UNPAIRED BONES
1. FRONTAL
2. OCCIPITAL
3. ETHMOID
4. SPHENOID

FACIAL BONES/ VISCEROCRANIUM (14 BONES)
PAIRED
1. MAXILLA
2. ZYGOMATIC
3. NASAL
4. LACRIMAL
5. PALATINE
6. INFERIOR NASAL CONCHA
UNPAIRED
1. VOMER
2. MANDIBLE

FOR GOOD POSITIONING IN SKULL RADIOGRAPHY CERTAIN REFERENCES ARE UTILIZED.
LANDMARKS LINES PLANES

LANDMARKS
 NASION - The articulation between nasal and frontal bones
 GLABELLA - A bony prominence on frontal bone immediately superior to
the nasion
 VERTEX - Highest point of skull in median sagittal plane
 EXTERNAL AUDITORY - Opening of external ear leading into external
MEATUS auditory canal
 EXTERNAL OCCIPITAL - A bony prominence on the occipital bone usually
PROTUBERANCE coincident with the median sagittal plane
 INFRAORBITAL - The inferior rim of the orbit
MARGIN
 INFRAORBITAL POINT - The lowest point on inferior orbital rim
 OUTER CANTHUS - Point where upper and lower eyelids meet laterally
OF THE EYE

Lines
 Inter-orbital (inter-pupillary) line: joins the centre of the
two orbits or the centre of the two pupils when the eyes are
looking straight forward.
 Infra-orbital line: joints the two infra-orbital points.
 Anthropological baseline: passes from the infra-orbital
point to the upper border of the external auditory meatus (also
known as the Frankfurter line).
 • Orbito-meatal base line (radiographic baseline):
extends from the outer canthus of the eye to the centre of the
external auditory meatus. This line is angled approximately 10
degrees to the anthropological baseline.

Planes
 Median sagittal plane: divides the skull into right and left halves.
Landmarks on this plane are the nasion anteriorly and the external
occipital protuberance (inion) posteriorly.
 Coronal planes: these are at right-angles to the median
sagittal plane and divide the head into anterior and posterior parts.
 Anthropological Plane: a horizontal plane containing the two
anthropological baselines and the infra-orbital line. It is an example of
an axial plane. Axial planes are parallel with this plane.
 Auricular plane: perpendicular to the anthropological plane.
Passes through the centre of the two EAM.

SKULL RADIOGRAPHY TECHNIQUES
ISOCENTRIC NON-ISOCENTRIC
UTILIZES SKULL UNITS
ADVANTAGES-
1. Highest quality image with reduced distortion
2. More comfortable to patient
3. Less dose and minimized secondary radiations
DISADVANTAGES-
1.Unsuitable for patients who are unable to cooperate
2.Technically demanding
3.Expensive
UTILIZES CONVENTIONAL EQUIPMENTS INCLUDING
X-RAY TABLE, BUCKY, GRID CASSETTES, SIMPLE X-RAY TUB
ADVANTAGES-
1. Cheaper
2. More versatile
DISADVANTAGES-
1. Poorer image quality
2. Less close collimation

SKULL: PROJECTIONS
STANDARD PROJECTIONS
LATERAL (SUPINE/ERECT)
OCCIPITOFRONTAL/POSTEROANTERIOR
HALF –AXIAL ANTEROPOSTERIOR 30 degree CAUDED(TOWNE’S)
SUBMENTOVERTICAL/BASAL

Lateral-supine with horizontal beam
Supine with head raised
Immobilized
MSP –L trolley & IOP-L cassette
Cassette lat to head & //MSP
CR directed //IOP &-L MSP
b/w glabella & EOP to 5cm
Superior to EOM
COLLIMATION:to skull size
Kvp 80-90
mAS 80-100
FFD 40”(120cm)
24*30cm(10*12”)
ATLS screening - #; sinus fluid levels ; free intracranial air

Where patient is more
cooperative
Bone malignancy
Metabolic bone disease
Sits facing erect bucky ;
MSP//bucky &IOP 90*bucky
CR directed //IOP &-L MSP
b/w glabella & EOP to 5cm
Superior to EOM
Kvp 80-90
mAS 80-100
FFD 40”(120cm)
CASSETTE- 24*30cm(10*12”)

Image should contain
-All cranial bones
-1st cervical vertebra
-Both inner & outer tables
TRUE LATERAL VIEW;
-Superimposition of both lateral
portion
Of floors of ACF & PCF
-superimposition of clinoid
processes
Of sella turcica

Fig. 53.2 (A) X-ray film of skull taken in standard lateral projection.B) Diagram to illustrate the
standard lateral view. 1 = coronal suture;2 = meningeal vascular marking, anterior branch; 3 =
anterior border ofmiddle fossa4lambdoid suture 5dorsum of sella 6 clivus 7lat sinus 8sq
parietal suture 9 EOM

1Frontal bone.
2Parietal bone.
3Occipital bone.
4Squamous portion, temporal bone.
5Petrous portion, temporal bone.
6Middle meningeal artery.
7Frontal sinus;;8Ethmoid sinus
9Maxillary sinus.
10Sphenoid sinus.
11Mastoid air cells.
12Transverse venous sinus.
13Sella turcica.
14Internal occipital protuberance.
15External occipital protuberance.
16Inner table.
17Diploe.
18Outer table.
19Parietal star
20Pinna of the ear.
21Internal auditory meatus.
22Temporomandibular joint.
23Nasopharynx.
24Hard palate.
25Orbit.
26Odontoid process.

CLINICORADIOLOGICAL CORRELATION
Lateral, Skull, Parietal Fracture. A linear fracture extends though the parietal bone (arrows). E.
Lateral Skull, Multiple Myeloma. Multiple, well-defined radiolucent lesions are visible
throughout the parietal and frontal bones.

OCCIPITOFRONTAL
kVp: 85 (80 to 90).
mAS-100
Film Size: 10 × 12 inches (24 × 30 cm), vertical orientation.
Grid: Yes.
TFD: 40 inches (102 cm); must correct for tube tilt with TFD to 37 inches (94 cm).
Tube Tilt: NO
Patient Position: Prone or upright.
Part Position: Frontal bone in contact with the bucky. Remove all lateral head tilt and rotation.
The orbitomeatal line should be perpendicular to the cassette.
CR: Exits through the nasion.
Collimation: To skull size.

Petrous ridges completely
superimposed within the orbit
Petrous ridges appears in the middle
third Of the orbit
Petrous ridges appear just below the
inferior orbital margin

kVp: 85 (80 to 90).
mAS-100
Grid: Yes.
TFD: 40 inches (102 cm); must correct for tube tilt with TFD to 37 inches (94 cm).
Tube Tilt: 15° caudad.
Patient Position: Prone or upright.
Part Position: Frontal bone in contact with the bucky. Remove all lateral head tilt and rotation.
The orbitomeatal line should be perpendicular to the cassette.
CR: Exits through the nasion.
SKULL: PA Caldwell’s Projection

Indicated in evaluation of
-sinus disease
Frontal bone
Orbits
sphenoid
Essential image characteristics
-all cranial bones
-Equidistance from a point in midline of skull
To lateral margins
-nasal septum & calcified penial gland in
midline
1 Frontal bone.
2 Frontal sinus.
3 Ethmoid sinus.
4 Maxillary sinus.
5 Nasal septum.
6 Petrous ridge.
7 Greater wing of sphenoid.
8 Infraorbital rim.
9 Supraorbital rim.
10 Nasal turbinates.
11Mandible.

Clinicoradiologic Correlations
D. PA Caldwell’s, Skull, Frontal Bone Fracture. The fracture is visible as multiple radiolucent
lines. The sinus is filled with hematoma (arrows). E. PA Caldwell’s, Skull, Frontal Sinus
Osteoma. Dense, ivory-like new bone fills a frontal sinus.

kVp: 85 (80 to 90).
mAS-100
Grid: Yes.
TFD: 40 inches (102 cm); must correct TFD to 35 inches (89 cm) for tube tilt.
Tube Tilt: 30 degree caudad.
Patient Position: Supine or upright.
Part Position: Centered, with removal of lateral head tilt and rotation. Orbito-meatal line is perpendicular to
the cassette.
CR: Passes through the midline at the external auditory meatus.
HALF-AXIAL FRONTO OCCIPITAL 30
DEGREE CAUDAD-
INDICATED in evaluation of
occipital bone
Petrous ridges
auditory meatus
zygoma
mandibular condyle

Towne's projection. (B) Diagram to illustrate (A) 1 = lateral sinus; 2 = foramen magnum; 3 =
dorsum sellae; 4 =i nternal auditory meatus; 5 = acuate eminence; 6 = superior semicircular
canal; 7 = lambdoid suture

1 Occipital bone.
2 Parietal bone.
3 Lambdoidal suture.
4 Sagittal suture.
5 Internal occipital protuberance.
6 Transverse venous sinus.
7 Petrous pyramids.
8 Mastoid air cells.
9 Foramen magnum.
10 Dorsum sellae.
11 Mandibular condyle.
12 Zygomatic arch.
13 Cervical pillar.
Essentials of image
The dorsum sellae and posterior
clinoid processes should project into
the anterior portions of the foramen
magnum.
All occipital bonem& posterior parts
of parietal bone & lambdoid suture
must be in included
Skull shouldn’t be rotated

D. AP Towne’s, Skull, Occipital Bone Fracture. A linear fracture extends through the occipital
bone (arrows). E. AP Towne’s, Skull, Occipital Bone Paget’s Disease. A sharply defined region of
decreased bone density is visible in the occipital bone (arrows), an indication of the osteolytic
phase Paget’s disease (osteoporosis circumscripta).
Clinicoradiologic Correlations

Erect/Pron,facing to bucky
Supported
MSP//midline-L cassette
OMP-L cassette
CR:30*Cranially to OMP
COLLIMATION:whole of occipital & parietal bones upto vertex
Avoid eyes
Kvp 80-90
mAS-80-100
FFD 40”

Supine/erect; neck hyperextended
Vertex in contact with cassette
EOM equidistant from cassette
MSP//midline&_Lcassette
OMP//cassette
CR: 90* OMP & centered midway b/w
EOMs
Kvp 80-90
mAS-90-100
Collimation ; to skull size
FFD 40”

Greater sphenoidal wing; 2 = sphenoidal sinus;
3 = foramen ovale; 4 = foramen spinosum; 5 = foramen lacerum medium; 6 = foramen magnus:
7 = internal auditory meatus

Indicated in evaluation of
-margins of skull base foramina
-trauma
- For fracture of zygomatic arch

Erect/Sitting, facing bucky & head is rotated so
MSP//BUCKY & IOP 90* BUCKY
SUPPORTED
CR:2.5cm vertically above a point 2.5cm along the baseline
From EOMs nearer to xray tube
kVp 80-90
mAS-90-100
FFD 40”
CASSETTE 10* 12”

Positioning & cassette : as
SMV
CR:20*caudally or
70*OMP
Centred in midline b/w
EOMs
OR
Head positioned with
OMP at 20*to
bucky,horizontal central
ray at 70* to baseplane.

ORBIT PROJECTION
PA SKULL
LATERAL SKULL
POSTEROANTERIOR OBLIQUE
INDICATED In evaluation of
-bony orbit details
-optic foramina for tumor
-blunt ocular trauma
-foreign bodies
-malignancy

Erect/prone ;examined side in contact
With bucky
Centre of examined side orbit should
Coincide with centre of bucky
MSP 35* VERTICAL OR 55* table
CR: centred to middle of bucky &
7.5cm above & behind the upper
Most EOM, CR emerges from
Centre of orbit
KVp 80-90
mAS-90-100
FFD40”
CASSETTE 10*12”
OPTIC FORAMINA: POSTERO-ANTERIOR OBLIQUE

TEMPORAL BONE
:PROJECTIONS
FRONTO-OCCIPITAL 35* CAUDAL
MASTOID PROFILE: LATERAL OBLIQUE25*
PETROUS PROFILE:ANTERO-
OBLIQUE(STENVER’S VIEW) Indicated in evaluation of
-otitis media
-basal tumors
-fractures
-changes in auditory canal
-congenital maldevelopment
-operative defects

supine/erect with back to bucky; head is adjusted so
EOMs equidistant from table & MSP 90* table
OMP 90* table
CR:35*OMP;centred midway b/w EOMs
KVp 80-90
mAS- 90-100
FFD 40”
COLLIMATION:from lateral margins of skull & suprainferiorly
To mastoid & petrous parts of temporal bone
Temporal bones

Sitting facing erect bucky; head rotated so that
MSP// bucky & IOL 90* BUCKY
Auricle adjacent to table folded forward
Mastoid in middle of bucky
CR:25*cadual angulation & centred 5cm above &2.5cm
Behind EOMs
KVp 80-90
mAS-90-100
FFD 40”
COLLIMATE to area under examination
Cassette 8*10”(18*24cm)

Prone/ sitting facing bucky,neck flexed so nose &
Forehead in contact with table ;OML 90* table.
-head rotated at45* so petrous part// cassette
CR:12* cephaled angulation,to saperate occiput
From petrous
Centred midway b/w EOP & EOM
KVp 80-90
mAS-90-100
FFD 40””
COLLIMATE to Mstoid & petrous
Parts of examined temporal
Cassette 8*10”(18*24cm)

an enlarged sella may be associated with a pituitary neoplasm, empty sella syndrome, or
extrapituitary mass (neoplasm, aneurysm); it may even be a normal variant.

Average (°) Minimum (°) Maximum (°)
137 123 152
The measurement is an index of the relationship between the anterior skull and its base. The
angle will increase beyond 152° in platybasia, in which the base is elevated in relation to the
rest of the skull. This may or may not be associated with basilar impression. The deformity
may be congenital (isolated impression, occipitalization) or acquired (Paget’s disease,
rheumatoid arthritis, fibrous dysplasia).
Basilar Angle

FACIAL BONES INCLUDING MANDIBLE

Facial bones
• Occipito-mental
• Modified mento-occipital
• Occipito-mental 30° caudad
• Modified reverse occipito-mental 30°
• Lateral
• Zygomatic arches: infero-superior
• Orbits: occipito-mental (modified)
• Nasal bones: lateral

• Position:
• Seated
• No rotation
• Orbitomeatal line @ 45° to cassette holder
• Centering :
• Lower orbital margin
• Exposure factor:
• kVP 75
• mAs 80

Essential image characteristic:
Petrous ridges must appear below the
floors of the maxillary sinuses

• Patients who have sustained trauma
• Often present supine on a trolley,
• In a neck brace
• With the radiographic baseline in a fixed position

• Position:
• Seated
• No rotation
• Centering :
• Top of cassette 5 cm
above the top of head
• kVP 75
• mAs 80

• Demonstrates lower orbital margins and orbital
floors en face.
• Zygomatic arches are opened out compared with OM
projection but they are still foreshortened.

• Position:
• Seated
• No rotation
• 30° caudad angulation
• Centering :
• Upper symphysis menti
• kVP 75
• mAs 80

Modified reverse
occipito-mental 30°

• Position:
• Supine
• No rotation
• Orbitomeatal line at 90° to table top
• Direction and Centering :
• Tube is angled 20 degree to the horizontal
• Upper symphysis menti
• 100 cm FFD
• kVP 85
• mAs 80

• Position:
• Supine/Erect
• No rotation
• Centering :
• 2.5 cm inferior to the
outer canthus of the eye
• kVP 75
• mAs 80

Zygomatic arches: infero-superior

• Position:
• Supine
• No rotation
• Cassette’s long axis // to axial plane of body
• Neck extended
• Head tilted 10° towards opposite side
• Centering :
• Midpoint of the
zygomatic arch and the
lateral border of the
facial bones
• kVP 75
• mAs 80

Orbits: occipito-mental
(modified)

• The projection is essentially an under-tilted occipito-
mental with the orbito-meatal baseline raised 10
degrees less than in the standard occipito-mental
projection
• Orbits circular rather than elliptical

• Position:
• Seated
• No rotation
• Centering :
• kVP 75
• mAs 80

• Position:
• Erect
• No rotation
• Centering :
• Nose
• kVP 45
• mAs 6

•Detected clinically & rarely treated
actively.
•Considering the dose of radiation to the
eye, this projection should be avoided.
•Severe nasal injuries will require only an
occipitomental projection to assess the
nasal septum and surrounding structures.

MANDIBLE
•Mandible: lateral 30° cephalad
•Mandible: postero-anterior
•Mandible: postero-anterior oblique
•Temporal-mandibular joints: lateral
•25° caudad

Mandible: lateral 30° cephalad

• Position:
• Supine
• No rotation
• MSP parallel to cassette
• Centering :
• CR is angled 30° cranially at an angle of 60 °
to cassette
• centred 5 cm inferior to angle of mandible
• kVP 75
• mAs 80

• Position:
• Erect
• No rotation
• Orbito meatal plane perp
to cassette
• Centering :
• Level of angle of mandible
• kVP 75
• mAs 80

Mandible:
Postero-anterior oblique
Demonstrates symphysis menti

• Position:
• Erect
• No rotation
• Orbito meatal plane perp to
cassette
• rotated 20°
• Centering :
• CR is directed perp to cassette
• centred 5 cm from the midline at level of angle of the
mandible.
• kVP 75
• mAs 80

Temporo-mandibular joints:
lateral 25° caudad

• Position:
• Erect
• No rotation
• Orbito meatal plane // to cassette.
• 1 cm along the OMB anterior to the external auditory
meatus.
• Centering :
• CR is angled 25° caudally and will be centred to a
point 5 cm superior to the joint remote from
the cassette so the central ray passes through
the joint nearer the cassette.
• kVP 75
• mAs 80

PNS
•Occipito-mental
•Occipito-frontal 15° caudad
•Lateral

 PARANASAL AIR SINUSES ARE A SERIES OF AIR FILLED CAVITIES LINED BY
MUCOUS MEMBRANE IN SOME OF THE BONES OF THE CRANIUM
 APPEARS OF HIGHER RADIOGRAPHIC DENSITYTHAN SURROUNDING
TISSUES
 SINUSES COLLECTIVELY CONSISTS OF THE FOLLOWING STRUCTURES-
• MAXILLARY SINUSES (MAXILLARY ANTRA)- PAIRED, PYRAMIDAL SHAPED
,LARGEST
• FRONTAL SINUSES- PAIRED, VARIABLE IN SIZE
• SPHENOID SINUSES- IMMEDIATELY BENEEATH SELLA TURCICA AND
POSTERIOR TO ETHMOID SINUSES
• ETHMOID SINUSES- SMALL AIR SPACES THAT COLLECTIVELY FORM PART OF
THE MEDIAL WALL OF THE ORBIT AND THE UPPER LATERAL WALLS OF THE
NASAL CAVITY

THIS PROJECTION IS DESIGNED TO PROJECT THE PETROUS PART
OF THE TEMPORAL BONE BELOW THE FLOOR OF THE
MAXILLARY SINUSES SO THAT FLUID LEVELS OR PATHOLOGICAL
CHANGES IN THE LOWER PART OF THE SINUSES CAN BE
VISUALIZED CLEARLY

• Position:
• Seated/ prone
• No rotation
• Centering :
• kVP 75
• mAs 80

•Essential image characteristic:
Petrous ridges must appear below the
floors of the maxillary sinuses

To distinguish a fluid level from
mucosal thickening, an additional
projection may be undertaken with
the head tilted, such that a transverse
plane makes an angle of about 20
degrees to the floor.

Occipito-frontal 15° caudad
Demonstrates the frontal and ethmoid sinuses

• Position:
• Seated
• No rotation
• Orbitomeatal line @15° to the horizontal
• Centering :
• Nasion
• kVP 75
• mAs 80
Essential characteristics: The petrous ridges should be projected just
above the lower orbital margin.

An OF10°↓ or occipito-frontal
projection would not be suitable for
demonstration of the ethmoid
sinuses, as the petrous ridges would
obscure the region of interest.

• Position:
• Erect
• No rotation
• Centering :
• 2.5 cm post. to outer
canthus of the eye
• kVP 75
• mAs 80
Essential image characteristics: Lateral portions of
the floors of the anterior cranial fossa are
superimposed

OPG
Rotational panoramic radiography
orthopantomography (OPT)
Dental panoramic tomography (DPT)
Panoral

Indications
• Orthodontic assessment of the teeth
• Detection # mandible
• Assessment of TMJ pathology
• Assess pathological lesions
• When intra-oral radiography is impossible
• Assessment of 3rd molars before surgical removal

Simultaneous
rotational
movement
Slit-collimated
vertical X-ray
beam
8° upward
inclination
focal trough
Principle

Factors reducing diagnostic quality of
image
• magnification variation
• tomographic blur
• overlap of adjacent teeth
• superimposition of soft tissue and secondary shadows
• limitations of resolution imposed by the image
receptor
• exposure parameters and processing conditions

10 to 30%
Objects lying closer to the X-ray source (i.e. situated inside the
focal trough) will display a greater degree of horizontal
magnification
Variability in horizontal shape is apparent by examining the
appearance of anatomical structures within the focal trough
(thetongue, hyoid bone) and those outside it (the zygomatic arch).

12- 20 s exposure
ski position
60 Kvp
20 mAs

Positioning of Frankfort plane upward
If the frankfort plane is rotated upward,it
results in overlapping of the images of the
teeth and an opaque shadow obcuring the root
of the max teeth

Superimposition of soft tissue and
secondary shadows
Superimposition of soft tissue and
secondary shadows

Limitations of resolution imposed by
image receptor, exposure parameters
and processing conditions
• Rushton et al. 1999 “one-third of all panoramic films
taken were diagnostically unacceptable”

Skull,orbit temporal bones,facial bones,paranasal sinuses,mandible and opg

Skull,orbit temporal bones,facial bones,paranasal sinuses,mandible and opg

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